Bis-(5-formyl furfuryl) ether and preparation method thereof

Abstract

The invention discloses bis-(5-formyl furfuryl) ether and a preparation method thereof, and belongs to the technical field of preparation of polymer precursors from biomass raw materials. The method comprises the following steps: dissolving 5-hydroxymethylfurfural in an organic solvent, and carrying out dehydration self-etherification reaction under the action of a Sn beta catalyst to obtain the bis-(5-formyl furfuryl) ether. Wherein the Sn beta catalyst is tin-modified dealuminated beta zeolite with Lewis acidity, is high in water resistance and stability, keeps relatively high catalytic activity in a reaction for preparing bis-(5-formyl furfuryl) ether through self-etherification of 5-hydroxymethylfurfural, and has the advantages of environmental friendliness, recyclability and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of preparing polymer precursors with biomass raw materials, and particularly relates to bis-(5-formylfurfuryl) ether and a preparation method thereof. Background Art

[0002] 5-Hydroxymethylfurfural (5-HMF) is an important platform compound with the advantages of high added value and wide applicability. It can be used as a monomer to synthesize bio-based materials, biofuels, pharmaceutical intermediates, liquid fuels and various chemical products, and has broad application prospects in green, low-carbon and sustainable development.

[0003] There are many value-added products derived from 5-HMF, such as 2,5-furandicarboxylic acid (FDCA), 2,5-furandicarboxaldehyde (DFF), 2,5-furan dimethanol (BHMF), bis-(5-formyl furfuryl) ether (OBMF), etc. Among them, OBMF is the product obtained by self-etherification of HMF, which can be used as a raw material to prepare polyamide and polyimide bio-based polymers. For example, the polymer obtained by the reaction of OBMF and 1,4-diaminobenzene has a high glass transition temperature, high thermal conductivity and electrical conductivity. In addition, OBMF can also be used to synthesize heterocyclic ligands and prepare hepatitis antiviral drug precursors. There are currently two synthetic pathways for OBMF reported in the literature: self-etherification of HMF and Williamson reaction of HMF and 5-chloromethylfurfural (CMF). Among them, the yield of OBMF synthesized from 5-HMF and CMF through Williamson reaction is only 43%. Traditional 5-HMF self-etherification is mainly based on homogeneous catalysts, such as p-toluenesulfonic acid / toluene system, and the yield can reach about 75%. The reason for the unsatisfactory yield is that alkylation by-products are formed between the reactants and the solvent. Homogeneous catalysts are easy to corrode equipment, and the products are difficult to separate and purify, so it is difficult to carry out large-scale industrial production.

[0004] In recent years, heterogeneous catalysts have attracted widespread attention for their advantages such as environmental friendliness, high catalytic efficiency, easy separation, and reusability. Therefore, researchers began to use heterogeneous acid catalysts to replace p-toluenesulfonic acid, such as using molecular sieves or loaded heteropoly acids, graphene oxide, ion exchange resins and other catalysts to prepare OBMF. Patent CN111233799B reports a method for synthesizing OBMF, using multi-level pore ZSM-5 molecular sieve as a catalyst to efficiently catalyze HMF self-etherification to prepare OBMF, with a yield of up to 96%. This method has the advantages of high yield and green environmental protection. Patent CN112300101B provides a method for preparing OBMF from 5-HMF, using metal trifluoromethanesulfonates with strong water resistance as catalysts, and can achieve efficient preparation of OBMF without removing water. In addition, the catalyst also has high catalytic efficiency, and is easy to recover and can be reused. However, the metals in the above-mentioned metal trifluoromethanesulfonates include rare metals and are expensive; although the multi-level pore molecular sieve has good acidity and stability, its expensive price also limits its practical application.

[0005] Based on this, in order to reduce the preparation cost of the catalyst and overcome the disadvantage of the traditional Lewis acid being unstable when in contact with water, the present invention develops a tin-modified dealuminated β zeolite catalyst Snβ for catalyzing the self-etherification of 5-HMF to prepare OBMF. The Snβ catalyst with Lewis acidity has high water resistance and stability, can maintain a high catalytic activity during the catalytic reaction, and has the advantages of being environmentally friendly and recyclable. Summary of the invention

[0006] One of the purposes of the present invention is to provide a method for preparing bis-(5-formylfurfuryl) ether, so as to solve the problem in the background technology that the yield of preparing OBMF by catalyzing 5-HMF with a conventional homogeneous acid catalyst is low and the purity of OBMF is poor;

[0007] The second object of the present invention is to provide a bis-(5-formylfurfuryl) ether prepared by the preparation method of bis-(5-formylfurfuryl) ether.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] In a first aspect, a method for preparing bis-(5-formylfurfuryl) ether comprises the following steps:

[0010] 5-Hydroxymethylfurfural is dissolved in an organic solvent, and dehydrated and self-etherified in the presence of Snβ catalyst to obtain bis-(5-formylfurfuryl) ether.

[0011] As a further embodiment of the present invention, the method for preparing the Snβ catalyst comprises the following steps:

[0012] Step 1. Pretreatment and impurity removal: SiO 2 / Al 2 O 3 =25(SiO 2 With Al 2 O 3 The beta zeolite having a molar ratio of 25) is calcined at 500-600° C. for 5-7 hours to remove the template and adsorbed impurities to obtain the treated beta zeolite;

[0013] Step 2. Nitric acid dealumination: place the treated β zeolite in 13.0 mol / L nitric acid solution, stir and react at 100°C for 18-22 hours, cool and filter, wash with deionized water until pH is neutral, and dry to obtain dealumination β zeolite, denoted as deAlβ;

[0014] Step 3. Tin-modified calcination: dealuminated β zeolite and tin chloride pentahydrate (SnCl 4 ·5H 2 O) grinding and mixing uniformly, heating to 500-600° C. and calcining for 5-7 hours to obtain a tin-modified dealuminated β zeolite Snβ catalyst.

[0015] As a further solution of the present invention, in step 3, the heating rate is 5°C / min.

[0016] As a further embodiment of the present invention, the Sn content in the Snβ catalyst is 1-10 wt % calculated based on the weight of the dealuminated β zeolite, which is marked as x wt % Snβ catalyst (x=1-10).

[0017] As a further solution of the present invention, the usage ratio of 5-hydroxymethylfurfural to organic solvent is 10-50g:1L.

[0018] As a further embodiment of the present invention, the organic solvent is at least one of toluene, ethylene dichloride, chloroform, p-chlorotoluene and mesitylene.

[0019] As a further solution of the present invention, the amount of the Snβ catalyst used is 10-50wt% of the mass of 5-hydroxymethylfurfural.

[0020] As a further solution of the present invention, the dehydration self-etherification reaction temperature is 60-120° C., and the dehydration self-etherification reaction time is 4-24 hours.

[0021] As a further solution of the present invention, after the dehydration self-etherification reaction is completed, a post-treatment step is required, specifically, first filtering to remove the Snβ catalyst, then rotary evaporation to remove the organic solvent, and finally drying to obtain bis-(5-formylfurfuryl) ether.

[0022] In a second aspect, a bis-(5-formylfurfuryl) ether prepared by the above preparation method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides a method for preparing bis-(5-formylfurfuryl) ether. By developing a Snβ catalyst with good water resistance and stability, the Snβ catalyst has Lewis acidity and can efficiently and stably catalyze the self-etherification of 5-HMF to prepare bis-(5-formylfurfuryl) ether. In addition, the Snβ catalyst also has the advantages of being environmentally friendly and recyclable.

[0025] 2. The method for preparing bis-(5-formylfurfuryl) ether from 5-hydroxymethylfurfural provided by the present invention has the advantages of high 5-hydroxymethylfurfural conversion rate, high product yield and less by-products. The prepared bis-(5-formylfurfuryl) ether can be used as a raw material to prepare polyamide and polyimide bio-based polymers. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 This is a BET (nitrogen adsorption) characterization diagram of the 6wt% Snβ catalyst prepared in Preparation Example 3 of the present invention;

[0028] Figure 2 1 is a scanning electron microscope (SEM) image of a 6 wt% Snβ catalyst prepared in Preparation Example 3 of the present invention; wherein (a) is a SEM image of a 6 wt% Snβ catalyst at a scale length of 500 nm, and (b) is a SEM image of a 6 wt% Snβ catalyst at a scale length of 200 nm;

[0029] Figure 3 is an X-ray photoelectron spectroscopy (XPS) diagram of the 6 wt% Snβ catalyst prepared in Preparation Example 3 of the present invention;

[0030] Figure 4 is an X-ray diffraction (XRD) diagram of a 6 wt% Snβ catalyst prepared in Preparation Example 3 of the present invention;

[0031] Figure 5 It is a Fourier transform infrared spectrum (FTIR) analysis chart of the 6 wt% Snβ catalyst prepared in Preparation Example 3 of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Preparation Example 1

[0034] The preparation method of 4wt% Snβ catalyst comprises the following steps:

[0035] Step 1. Pretreatment and impurity removal: β zeolite (SiO 2 / Al 2 O 3 =25) calcined at 550°C for 6h to remove the template and adsorbed impurities to obtain treated β zeolite;

[0036] Step 2. Nitric acid dealumination: place the treated β zeolite in a 13.0 mol / L nitric acid solution, stir and react at 100°C for 20 h, cool and filter, wash with deionized water until the pH is neutral, and dry at 100°C to obtain deAlβ;

[0037] Step 3. Tin-modified calcination: According to the weight of the dealuminated β-zeolite, 3 g of dealuminated β-zeolite and 0.37 g of SnCl 4 ·5H 2 O was finely ground for 1 hour to mix evenly, then heated to 550°C at a rate of 5°C / min in an air atmosphere and calcined for 6 hours to obtain a 4wt% Snβ catalyst.

[0038] Preparation Example 2

[0039] The preparation method of 2wt% Snβ catalyst comprises the following steps:

[0040] Step 1 and step 2 are the same as in Preparation Example 1;

[0041] Step 3. Tin-modified calcination: According to the weight of the dealuminated β-zeolite, 3 g of dealuminated β-zeolite and 0.18 g of SnCl 4 ·5H 2 O was finely ground for 1 hour to mix evenly, then heated to 550°C at a rate of 5°C / min in an air atmosphere and calcined for 6 hours to obtain a 2wt% Snβ catalyst.

[0042] Preparation Example 3

[0043] The preparation method of 6wt% Snβ catalyst comprises the following steps:

[0044] Step 1 and step 2 are the same as in Preparation Example 1;

[0045] Step 3. Tin-modified calcination: According to the weight of dealuminated β-zeolite, 3 g of dealuminated β-zeolite and 0.56 g of SnCl 4 ·5H 2 O was finely ground for 1 hour to mix evenly, then heated to 550°C at a rate of 5°C / min in an air atmosphere and calcined for 6 hours to obtain a 6wt% Snβ catalyst.

[0046] Preparation Example 4

[0047] The preparation method of 8wt% Snβ catalyst comprises the following steps:

[0048] Step 1 and step 2 are the same as in Preparation Example 1;

[0049] Step 3. Tin-modified calcination: According to the weight of the dealuminated β-zeolite, 3 g of dealuminated β-zeolite and 0.77 g of SnCl 4 ·5H 2 O was finely ground for 1 hour to mix evenly, then heated to 550°C at a rate of 5°C / min in an air atmosphere and calcined for 6 hours to obtain an 8wt% Snβ catalyst.

[0050] The performance of the 6wt% Snβ catalyst prepared in Preparation Example 3 was tested:

[0051] (1) BET characterization of 6wt% Snβ catalyst Figure 1 As shown, from Figure 1 It can be seen that its BET specific surface area is 662.49 m 2 / g, pore diameter is 10nm, pore volume is 0.17cm 3 / g, the adsorption amount increases at low relative pressure and jumps at high relative pressure, which indicates that the prepared molecular sieve material has a mesoporous structure and a high specific surface area, which is beneficial to the adsorption and desorption of reaction substrates. At the same time, the smaller pore volume is not conducive to the entry of large molecular products, which can effectively avoid the destruction of products.

[0052] (2) SEM characterization of 6wt% Snβ catalyst Figure 2 As shown, the scale length of (a) is 500nm, and the scale length of (b) is 200nm; it can be seen from the SEM image that the catalyst has a significant pore structure and high dispersion, and this structure has a significant positive effect on the adsorption of the substrate and the provision of Lewis acid acidity.

[0053] (3) XPS characterization of 6wt% Snβ catalyst Figure 3 As shown, from the XPS graph it can be seen that the catalyst has Sn, O, Si and Al elements.

[0054] (4) XRD characterization of 6wt% Snβ catalyst Figure 4 As shown, no bulk SnO was detected in XRD. 2 This indicates that the Sn species are highly dispersed on the molecular sieve support.

[0055] (5) FT-IR characterization of 6wt% Snβ catalyst Figure 5 As shown, from FT-IR, we can see that 1627cm -1 The peak corresponds to the bending vibration of adsorbed water in the molecular sieve, 1240 cm -1 The peak at 1112 cm is related to the stretching vibration of Si-O-Sn or Al-O-Sn bonds in the skeleton. -1 Corresponding to the antisymmetric stretching vibration of Si-O-Si bond in the molecular sieve framework, 791 cm -1 Related to the vibration of Sn-O bond, Si-O bond or Al-O bond in the molecular sieve framework, 625cm -1 The peak at 577 cm-1 may be related to the bending vibration of Si-O bond or Al-O bond in the molecular sieve framework. -1 The peak at may be related to the bending vibration of Si-O bond or Al-O bond in the molecular sieve framework.

[0056] In summary, the 6wt% Snβ catalyst is a catalyst with a porous, large specific surface area and mesoporous structure. The Sn in the catalyst is highly dispersed, and obvious interaction between Sn and the carrier can be observed, which provides a basis for the catalyst stability and the manifestation of Lewis acidity.

[0057] Example 1

[0058] A method for preparing bis-(5-formylfurfuryl) ether comprises the following steps:

[0059] 252 mg of 5-HMF (2 mmol), 10 mL of toluene and 75 mg of the 6 wt % Snβ catalyst prepared in Preparation Example 3 were added to a 35 mL pressure tube in sequence, and the mixture was reacted at 100° C. for 12 h.

[0060] After the reaction was completed, the mixture was cooled to room temperature and sampled for HPLC detection. The detection conditions were: high performance liquid chromatography, C18 column, 4.6*250nm, 5um; mobile phase methanol: 0.1% phosphoric acid aqueous solution gradient elution, the initial mobile phase ratio was 10:90, and the ending ratio was 90:10; flow rate: 1.0 ml / min; column temperature: 35°C; detector: UV, detection wavelength: 282 nm, and the measured OBMF yield was 98.6%.

[0061] The reaction solution was filtered to collect the catalyst, the filtrate was subjected to rotary evaporation to remove the organic solvent, and the solid OBMF product was obtained after drying, and the purity was measured to be 99.5%.

[0062] Example 2

[0063] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only 6wt% Snβ catalyst is replaced by 2wt% Snβ catalyst prepared in Preparation Example 2, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 92.7%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.3%.

[0064] Example 3

[0065] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only 6wt% Snβ catalyst is replaced by 4wt% Snβ catalyst prepared in Preparation Example 1, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 95.6%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 99.5%.

[0066] Example 4

[0067] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only 6wt% Snβ catalyst is replaced by 8wt% Snβ catalyst prepared in Preparation Example 4, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 97.1%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.6%.

[0068] Example 5

[0069] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only toluene is replaced by ethylene dichloride, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 83.3%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.1%.

[0070] Example 6

[0071] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only toluene is replaced by chloroform, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 85.6%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.3%.

[0072] Example 7

[0073] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only toluene is replaced by p-chlorotoluene, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 91.5%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 98.9%.

[0074] Example 8

[0075] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only toluene is replaced by mesitylene, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 89.6%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.4%.

[0076] Example 9

[0077] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the reaction temperature is replaced with 60° C., and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 86.7%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 98.5%.

[0078] Example 10

[0079] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the reaction temperature is replaced with 90° C., and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 98.3%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 98.6%.

[0080] Embodiment 11

[0081] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the reaction temperature is replaced with 120° C., and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 98.5%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 99.2%.

[0082] Example 12

[0083] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the reaction time is replaced with 4 hours, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 95.1%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 98.7%.

[0084] Example 13

[0085] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the reaction time is replaced with 20 hours, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 98.8%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 98.6%.

[0086] Embodiment 14

[0087] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the reaction time is replaced with 24h, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 97.3%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.0%.

[0088] Embodiment 15

[0089] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the amount of 6wt% Snβ catalyst is replaced with 25.2mg, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 97.2%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 98.7%.

[0090] Example 16

[0091] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the amount of 6wt% Snβ catalyst is replaced with 126mg, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 98.7%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 99.4%.

[0092] Embodiment 17

[0093] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the amount of toluene is replaced by 25.5 mL, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 92.1%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 99.6%.

[0094] Embodiment 18

[0095] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that only the amount of toluene is replaced with 5.5 mL, and the other components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 95.3%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 98.4%.

[0096] Embodiment 19

[0097] The 6wt% Snβ catalyst filtered and recovered in Example 1 was washed with ethanol and deionized water, dried, and then put into the preparation reaction of bis-(5-formylfurfuryl) ether, wherein the amount ratio of 5-HMF, toluene and 6wt% Snβ catalyst was the same as that in Example 1, and the reaction temperature and time were kept consistent; after the reaction, the OBMF yield was measured to be 93.2%, and the solid OBMF was obtained after post-treatment, and the purity was measured to be 98.7%.

[0098] Comparative Example 1

[0099] A method for preparing bis-(5-formylfurfuryl) ether, which is different from that of Example 1 in that 6wt% Snβ catalyst is replaced by β zeolite (SiO 2 / Al 2 O 3 =25), and the other components and steps are completely the same. After the reaction is completed, the yield of OBMF is measured to be 52.3%, and the solid OBMF is obtained after post-treatment, and the purity is measured to be 93.1%.

[0100] Comparative Example 2

[0101] A method for preparing bis-(5-formylfurfuryl) ether, which is different from Example 1 in that 6wt% Snβ catalyst is replaced by deAlβ, and the remaining components and steps are completely the same. After the reaction is completed, the OBMF yield is measured to be 30.6%, and solid OBMF is obtained after post-treatment, and the purity is measured to be 91.4%.

[0102] The relevant reaction parameters in Example 1 to Example 18 and Comparative Example 1 to Comparative Example 2 are shown in Table 1.

[0103] Table 1

[0104]

[0105]

[0106] The yield and purity of the product OBMF of Example 1 to Example 18 and Comparative Example 1 to Comparative Example 2 are summarized in Table 2.

[0107] Table 2

[0108]

[0109]

[0110] As can be seen from Table 2, the Snβ catalyst recovered in Example 1 is used again in the preparation of OBMF after washing with ethanol and water, and still has a high catalytic activity, indicating that the Snβ catalyst has high stability and good water resistance; by comparing Example 1 with Comparative Example 1 and Comparative Example 2, nitric acid is used as a dealuminizing agent, and aluminum ions in β zeolite are removed by chemical reaction to form vacancies, thereby improving the acidity of β zeolite; by mixing and calcining with tin chloride pentahydrate, tin ions are introduced into the zeolite framework to form a tin-modified Snβ catalyst. The introduction of tin not only enhances the acidic properties of the catalyst, but also improves the catalytic activity by occupying vacancies. The Lewis acidic Snβ catalyst developed by the present invention has high water resistance and stability, can efficiently and stably catalyze the self-etherification of 5-HMF to prepare OBMF, and can improve the reaction conversion rate and yield by changing parameters such as reaction temperature, time, and solvent type. In addition, the OBMF prepared by the present invention has a high purity and can be used as a raw material to prepare polyamide and polyimide bio-based polymers.

[0111] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0112] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing bis-(5-formylfurfuryl) ether, characterized in that: The steps include: 5-Hydroxymethylfurfural is dissolved in an organic solvent, and dehydrated and self-etherified in the presence of a Snβ catalyst to obtain bis-(5-formylfurfuryl) ether.

2. The method for preparing bis-(5-formylfurfuryl) ether according to claim 1, wherein: The preparation method of the Snβ catalyst comprises the following steps: Step 1. Pretreatment and impurity removal: calcining the β zeolite with SiO2 / Al2O3=25 at 500-600°C for 5-7h to remove the template and adsorbed impurities to obtain the treated β zeolite; Step 2. Nitric acid dealumination: placing the treated β zeolite in a 13.0 mol / L nitric acid solution, stirring and reacting at 100°C for 18-22 hours, cooling and filtering, washing with deionized water until the pH is neutral, and drying to obtain dealumination β zeolite; Step 3. Tin-modified calcination: Grind and mix the dealuminated β zeolite and tin chloride pentahydrate evenly, heat to 500-600° C. and calcine for 5-7 hours to obtain a Snβ catalyst.

3. The method for preparing bis-(5-formylfurfuryl) ether according to claim 2, wherein: In step 3, the heating rate is 5°C / min.

4. The method for preparing bis-(5-formylfurfuryl) ether according to claim 2, wherein: The Sn content in the Snβ catalyst is 1-10wt% calculated based on the weight of the dealuminated β zeolite.

5. The method for preparing bis-(5-formylfurfuryl) ether according to claim 1, wherein The dosage ratio of the 5-hydroxymethylfurfural to the organic solvent is 10-50g:1L.

6. The method for preparing bis-(5-formylfurfuryl) ether according to claim 1, wherein: The organic solvent is at least one of toluene, ethylene dichloride, chloroform, p-chlorotoluene and mesitylene.

7. The method for preparing bis-(5-formylfurfuryl) ether according to claim 1, characterized in that: The amount of the Snβ catalyst used is 10-50wt% of the mass of 5-hydroxymethylfurfural.

8. The method for preparing bis-(5-formylfurfuryl) ether according to claim 1, characterized in that: The dehydration self-etherification reaction temperature is 60-120° C., and the dehydration self-etherification reaction time is 4-24 hours.

9. The method for preparing bis-(5-formylfurfuryl) ether according to claim 1, characterized in that: After the dehydration self-etherification reaction is completed, a post-treatment process is required, including filtering to remove the Snβ catalyst, then rotary evaporation to remove the organic solvent, and finally drying to obtain bis-(5-formylfurfuryl) ether.

10. A bis-(5-formylfurfuryl) ether, characterized in that Prepared by the preparation method described in claim 1.

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